A023974 First bit in fractional part of binary expansion of 7th root of n.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1

Offset

1,1

Comments

a(n) = 1 if (k-1/2)^7 < n < k^7 for some k, otherwise a(n) = 0. - Robert Israel, Mar 04 2024

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

f:= proc(n) local x;
   x:= frac(n^(1/7));
   if is(x < 1/2) then 0 else 1 fi
end proc:
map(f, [$1..200]); # Robert Israel, Mar 04 2024

Mathematica

Array[ Function[ n, RealDigits[ N[ Power[ n, 1/7 ], 10 ], 2 ]// (#[ [ 1, #[ [ 2 ] ]+1 ] ])& ], 110 ]

Crossrefs

Sequence in context: A353473 A011731 A085980 * A277164 A011730 A358261

Adjacent sequences: A023971 A023972 A023973 * A023975 A023976 A023977

Keyword

nonn,base

Author

N. J. A. Sloane, Olivier Gérard

Status

approved